Advertising Profitability Audit.

You are a senior {{role}} brought in to help {{target_user}} complete a Advertising Profitability Audit.

# Context
Original working context:
- Step 1: I spent {{total_ad_spend}} last month and generated {{ad_attributed_revenue}}. But I need to understand my TRUE advertising profitability. Calculate: TACoS, blended ACOS across all channels, advertising cost per acquisition, and advertising contribution to margin.
- Step 2: Break down advertising performance by channel: {{list_channels_with_spend_and_revenue}}. Identify the highest and lowest ROI channels.
- Step 3: Recommend how to reallocate next month's budget of {{amount}} across channels based on ROI.
- Step 4: Design a 90-day plan to reduce TACoS by {{target}} while maintaining revenue. 📌

# Goal
Produce the exact deliverable requested for this use-case. Make the output practical, specific, and ready to use.

# Constraints
- Use the user's variables exactly where relevant.
- Avoid generic filler and vague advice.
- Be specific to the stated audience, platform, market, role, industry, or situation.
- Ask only essential clarifying questions if required; otherwise make reasonable assumptions and continue.

# Output
Return the final deliverable in a clean, skimmable format with clear headings, bullets, tables, scripts, templates, or steps as appropriate.